In bacteria, reproduction typically occurs through a process called binary fission, where a single parent cell divides to produce two daughter cells, each genetically identical to the parent. When considering the third generation of a bacterium, the matching DNA sequences can be calculated based on the principle of inheritance in binary fission.
For simplicity:
- The original parent cell (generation 0) has 100% of its DNA.
- The first generation (generation 1) is a clone of the parent and also has 100% matching DNA.
- The second generation (generation 2) is a clone of the first generation and will also have 100% matching DNA.
- The third generation (generation 3), which is a clone of the second generation, will likewise have 100% matching DNA.
Thus, the original parent cell and the third generation will have 100% matching DNA sequences.
Therefore, the correct answer would be:
100%